The electoral setback suffered by the French Communist Party (PCF) in the 1981 elections was of unexpected proportions, the only comparable precedent being that of 1958; however, the mechanisms involved and the significance of the 1981 result aredifferent. In the presidential election the decline was both massive and relatively homogeneous. The PC was affected equally in those areas where it was electorally weak and in areas where il was strong, the latter failing, unlike 1958, to offer stiffer resistance — quite the contrary in fact. Interpreting this setback in terms of the " useful vote " requires clarification as to the possible meanings of this concept. The technical and tactical factors constituted by the mechanical effect of the natu...